#pragma once

namespace base {
// Do not declare a NotificationSource directly--use either
// "Source<sourceclassname>(sourceclasspointer)" or
// NotificationService::AllSources().
class NotificationSource {
public:
  NotificationSource(const NotificationSource &other) : ptr_(other.ptr_) {}
  ~NotificationSource() {}

  // NotificationSource can be used as the index for a map; this method
  // returns the pointer to the current source as an identifier, for use as a
  // map index.
  uintptr_t map_key() const { return reinterpret_cast<uintptr_t>(ptr_); }

  bool operator!=(const NotificationSource &other) const {
    return ptr_ != other.ptr_;
  }
  bool operator==(const NotificationSource &other) const {
    return ptr_ == other.ptr_;
  }

protected:
  explicit NotificationSource(const void *ptr) : ptr_(ptr) {}

  // Declaring this const allows Source<T> to be used with both T = Foo and
  // T = const Foo.
  const void *ptr_;
};

template <class T> class Source : public NotificationSource {
public:
  // TODO(erg): Our code hard relies on implicit conversion
  Source(const T *ptr) : NotificationSource(ptr) {} // NOLINT
  Source(const NotificationSource &other)           // NOLINT
      : NotificationSource(other) {}

  T *operator->() const { return ptr(); }
  // The casts here allow this to compile with both T = Foo and T = const Foo.
  T *ptr() const { return static_cast<T *>(const_cast<void *>(ptr_)); }
};
} // namespace base
